Smart Text Reflow and conditional text

I have experienced this situation when working with conditional text and Smart Text Reflow: I set up a document to use Smart Text Reflow, linking frames as described in Help files on regular pages (not masters). My text frames were sized so they did not fill the full column depth--they aligned at the bottom to a guide about 6p above the bottom margin guide. I deselected the Limit to Master Frames check box in Preferences and selected Delete Empty Pages. Then I applied conditional formatting to various sections of the text. When I hid some conditional text, the document ''contracted'' just the way it was supposed to, with empty pages being deleted. However, when I redisplayed the hidden conditional text, some text frames in the last page or two of the document expanded past their original guide to fill the entire page columns, right down to the margin guide. I have tried a number of variations of these steps to try to prevent this expansion of text frames, with no success. When I tried to set up text frames on masters, and used the Limit to Master Frames option, after I hid the conditional text and redisplayed it, the original pages refused to reappear and I got an overset indicator. Clearly I don't understand something about how to link the master frames to allow the text to flow, but Help files are not helpful! I worked around this problem by simply changing my bottom margin to contain the conditional text when it was unhidden. Any advice would be greatly appreciated.